Abstract
Purpose: :
We have formed a clinical impression that children with amblyopia secondary to incomitant strabismus are more likely to fail occlusion treatment than those with concomitant strabismus. There is limited data regarding this association in the literature with most information focussing on the surgical outcomes. We aim to investigate whether incomitant squints are associated with poorer visual outcome than concomitant squints.
Methods: :
All incomitant squints with amblyopia presenting to the Bristol Eye Hospital between 1998 and 2002 were reviewed. 8 cases were identified. Sixteen age and sex matched concomitant squints were retrospectively identified as controls. All cases and controls underwent occlusion therapy and correction of refractive error if present.
Results: :
No concurrent ocular pathology affecting visual acuity was found. 62.5% (5/8) of incomitant cases presented with visual acuities worse than or equal to 6/36, compared to only 37.5% (6/16) of concomitant controls. Poor compliance with occlusion was more frequently noted in the case group than the control group. Following treatment, 62.5% (5/8) incomitant cases had a deterioration in visual acuity compared to 31.25% (5/16) controls. Final visual acuity was worse than 6/9 in 100% of cases compared with 57.4% of controls (p<0.001), and worse than 6/36 in 50% of cases compared with only 8.3% of controls (p<0.001). 42.8% of controls achieved greater than or equal to 6/9, comparable with the literature (40–73% of strabismic/anisometropic amblyopia improve to > 6/9 after occlusion1,2,3 ).
Conclusions: :
Outcome of amblyopia treatment is worse in incomitant strabismus. Early onset strabismus plus a lack of fixation with the paretic eye in this group result in a prognosis that is more like unilateral congenital cataract rather than congenital esotropia. We suggest that in these cases, the clinician should commence maximal occlusion therapy early and encourage parents to persevere with treatment. Early surgery may be indicated to facilitate fixation without abnormal head posture and improve compliance with occlusion therapy to maximise the chances of successful amblyopia treatment. 1 Hiscox et al. Eye. 1992;6:300–4
2 Woodruff et al. Eye 1994;8:627–31
3 Beardsell et al. Pediatr Ophthalmol Strabismus 1999;36:19–24
Keywords: strabismus: treatment • amblyopia • infant vision